The work is devoted to investigation of new nanostructural photosensitizer on a base of zinc octa-4,5-decylthio-3,6-chloro-phthalocyanine solubilized in micellar dispersion. Photosensitizer possesses its absorption maximum at about 730 nm and can be considered promising for PDT treatment of tumors. Optimization of content and proportion of components in composition allowed to achieve high stability of nanostructural properties of dispersion stored at room temperature. Photosensitizer shows high selectivity of accumulation in tumor which achieves the values of 5-8 by 3-5 hours, and 8-18 – by 24 hours after intravenous administration. Maximum concentration of photosensitizer in tumor is observed in the range of 5-24 hours after its administration. Photosensitizer quickly clears from the normal tissue, its level in skin decreases down to detection threshold by 6-7 days after administration. For PDT, tumors were irradiated using 732 nm laser with power density in a range of 100 to 300 mW/cm2 and treatment duration of 20-30 min, starting 5 hours after administration of photosensitizer. Tumor growth inhibition for Erlich tumor achieved 100% for most of animals.